<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        /* 
            ID > CLASS > DIV
        */
         #item{
            color: green;
        }
        .box{
            color: blue;
        }
        div{
            color: red;
        }
    </style>
</head>
<body>
    <div class="box" id="item">
        我是一个孤独的DIV
    </div>
</body>
</html>